Stereophonic reproduction apparatus



Sept. 16, 1952 K. DE BOER 2,610,694

STEREOPHONIC REPRODUCTION APPARATUS Filed April 8, 1946 LOUDSPEAABQS jl i --I-} Z1 REP TwN Q {4' i i APPARATUS I l I a L; i i I 1 E 1 fl iv; 3 LOWFREGUE/VCY LOUDSPEAKEI? I N V EN TOR. KOIZNHIS DIBUZ R ATTOBNEX Patented Sept. 16, 1952 STEREOPHONIC REPRODUCTION APPARATUS Kornelis "de Boer, -Eindhoven, Netherlands, 1 assignonhy mesnei assignments, to' HartfordNa- .tional .Bank and Trust Company, T'Hartford,

Conn as trustee Application April 8, 194.6,"Serial N0."660,'324 IntheNetherlandsMay 30,1944

Section 1," Public'Law 690,-August 8,1946 ..Patent expires May 30, 1964 This invention relates tollstereophonic' reproducing apparatus in which at least'two spaced loudspeakers are used. Such apparatus may be used, for example, in radio orphonograph sets.

The spacing between the loudspeakers is known to be very important in producing a stereophonic effect. The larger the spacing is,'the greater'is the effect. It may also be desirable to vary the spacing in view of variationsin size of the original sound source. If, for example, the sound of a large band or orchestra is being'reproduced, it is desirable to increase the volume of the sound image during reproduction over that'of asmall orchestra.

Generally, it is most desirable to minimiz the size of the reproduction apparatus in order to obtain a compact arrangement. Prior attempts in achieving this goal in stereophonic reproducing systems include the mounting of two loudspeakers on extension panels, whichwere preferably fitted on the front wall, to vary the spacing between the loudspeakers in accord with the desired stereophonic effect.

However, this form of construction has the disadvantage that the construction of these panels must be relatively heavy and consequently, they are more costly than is necessary. Furthermore, the supply wires for the loudspeakers have to follow the sliding movement continuously so that when in regular use, the wires may be-damaged and broken.

One of the objects of the present invention is to achieve the aforesaid goal in stereophonic reproduction apparatus having a variable stereophonic effect. According to the invention, at least one of the loudspeakers is housed in one of the side walls of the cabinet so as to be stationary. Pivotally mounted on the same side wall is a hinged panel which covers the loudspeaker but which is swingable to open positions to reflect the sound oscillations coming from this loudspeaker primarily in about the same direction as that in which the sound is emanated from the other loudspeakers housed in the cabinet. This panel may be simply hinged to the rear of the side wall of the apparatus so as to be movable with respect to the loudspeaker mounted on said side wall.

The hinged panels used preferably have sound distributing elements fitted to their inner sides so that correct reproduction is ensured in all directions, because, as is well known, even the high tones, which are radiated by the loudspeaker at a smaller angle than the low tones, are distributed in this case.

In order that the invention may be clearly uriderstoodand readily carried intoeffect, it will nowbe set forth more fully'with reference to the accompanying drawing in which:

Fig.1 lis a diagrammatic plan representation of an embodiment of'the invention by way Of'BX- ampleyand 'Fig. 2 is a perspective view of a fragment of one of the panels shown 1 tofshow the sound distributing elements more clearly.

Referring to Figure 1 of the drawing, reference numeral"! designates a radio'receiver set in which. is enclosed, stereophonic reproducing apparatus as shown diagrammatically by legend.

LoudspeakersLi and L2, which are high frequency loudspeakers for the high tones, arefitted in the two .side walls. Low frequency loudspeaker L3 is, housed in the'front wall and reproduces frequencies, for examplegbelow 300 cycles per second.

The side walls canv be covered by hinged panels K1 and K2. .In the out-position, it is preferred that. the. angle between the'panel and the side wall does not exceed and in any event, it should be-less than Thesepanels K1 and vK22 reflectthe sound emanating from loudspeakers L1 and L2 respectively, primarily'in' about the same direction as that in which the sound is emanated from loudspeakerLa.

In order that the high tones radiated by the loudspeakers L1 and L2 maybe evenly distributed, the side panelsKi and'Kz are preferably provided with sound distributing elements 4, such as small cones and thelike as more clearly illustrated in Figure 2 for example.

What I claim is:

1. stereophonic reproduction apparatus, comprising a cabinet structure having a front wall and side walls, a plurality of loudspeakers, at least one of said loudspeakers being for high frequency sound production and housed in one of said side walls so as to be stationary, a covering for said one of said loudspeakers comprising a hinged panel attached to said cabinet structure, at least another of said loudspeakers being for low frequency sound production and housed in said front wall, said hinged panel being swingable to a position in front of said one of said loudspeakers for reflecting the sound oscillations coming therefrom primarily in about the same direction as that in which the sound is radiated from said another of said loudspeakers, said hinged panel being provided on its inner side with sound distributing elements.

2. stereophonic reproduction apparatus, comprising a cabinet structure having a front wall tion, a hinged panel attached to each of said 7 side walls and positioned to substantially cover one of said high frequency sound production loudspeakers housed therein, said hinged panels being movable to positions for reflecting the sound oscillations coming from said high frequency sound production loudspeakers primarily in about the same direction as that in which the sound is radiated from said low frequency sound production loudspeaker, each of said hinged panels being provided on its inner side with sound distributing elements.

3. Stereophonic reproduction apparatus comprising a cabinet structure having a front wall and side walls, reproduction apparatushoused in said cabinet structure, a plurality of loudspeakers, at least one of said loudspeakers being for low frequency sound reproduction and housed in said front wall for directing sound in one direction, means separately connecting said low frequency loudspeaker to said reproduction apparatus to form therewith a stereophonic component channel, at least another of said loudspeakers being for high frequency sound production and housed in one'of the side walls so as to be stationary and for directing sound at an angle to said first direction, other means separately connecting said high frequency loudspeaker to said reproduction apparatus to form therewith another stereophonic component channel, a covering for said high frequency loudspeaker comprising a sound reflecting hinged panel attached to said side wall of said cabinet structure in which one of said loudspeakers is located, said hinged panel being swingable to a position in front of said one of said loudspeakers for reflecting the sound oscillations coming therefrom primarily in about the same direction as that in which the sound is radiated from said low frequency loudspeaker.

4. Stereophonic reproduction apparatus con prising a cabinet structure having a front and a pair of side walls, a loudspeaker housed in each one of said walls, the loudspeaker housed in said front Wall being for low frequency sound production and directing sound in a first direction, the loudspeakers housed in said side walls being for high frequency sound production and each direct- 4 ing sound at an angle to said first direction, a sound deflecting hinged panel attached to each of said side walls and positioned to substantially cover the loudspeakers housed therein, said hinged panel being movable to positions for refleeting the sound oscillations coming from said high frequency sound production loudspeakers primarily in about the same direction as that in which the sound is radiated from said low frequency sound production loudspeaker.

5. Stereophonic reproduction apparatus comprising a cabinet having a front wall and side Walls, a reproduction apparatus housed in said cabinet, at least one loudspeaker for high frequency sound production and housed in one of said walls so as to direct sound in a first direction, at least another loudspeaker for low frequency sound production and housed in another of said walls so as to direct sound at an angle to said first direction, means separately connecting each of said loudspeakers to said reproduction apparatus to form therewith a pair of stereophonic component channels, a sound reflecting hinged panel attached to that side wallon which one of said loudspeakers has been secured and positioned to substantially cover said loudspeaker, said hinged panel being swingable to a position in front of said'loudspeaker in the side wall for reflecting the sound oscillations coming therefrom primarily in about thesame direction as that in which the sound is radiated from the other loudspeaker.

KORNELIS in: BOER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,915,954 Scofield June 27, 1933 1,932,343 Holland Oct. 24, 1933 2,114,680 Goldsmith Apr. 19, 1938 2,217,279 Karns Oct. 8, 1940 2,410,413 Hurley Nov. 5, 1946 FOREIGN PATENTS Number Country Date 758,706 France Nov. 7, 1933 404,937 Great Britain Jan. 15, 1934 790,599 France Sept. 9, 1935 551,364 Great Britain Feb. 18, 1943 

